Prosecutors have described the 48-year-old US citizen as one of the top protein biochemists in the world. She had worked at GlaxoSmithKline’s research facility in suburban Philadelphia for about a decade and had become a senior manager.

A cancer researcher pleaded guilty on Friday to conspiring to steal biopharmaceutical trade secrets from GlaxoSmithKline in what prosecutors said was a scheme that involved plans to set up companies in China to market them.Yu Xue entered a guilty plea in federal court on Friday to a single conspiracy count. The government dropped more than two dozen other pending counts against the researcher as part of the plea.

In court on Friday, Xue said she didn’t understand that the material she was emailing to her private account then to others including portions of her own patent application for certain research was considered trade secrets. “A trade secret to me is not publicly available. The patents I sent to them is publicly available,” she said, noting that she sent the preliminary application for a patent on her research.

Judge Joel Slomsky noted that prosecutors did not have to prove that she understood it was a trade secret, but that she knew she was sharing confidential materials. Slomsky said he believed federal prosecutors had met that burden of proof.

Prosecutors have described the 48-year-old US citizen as one of the top protein biochemists in the world. She had worked at GlaxoSmithKline’s research facility in suburban Philadelphia for about a decade and had become a senior manager. She was fired shortly after charges were brought against her in early 2016.

Prosecutors had accused her of downloading and emailing confidential information including research on specific cancer drugs and working with four others, including two people in China, charged in connection with the scheme.

Another research scientist at GlaxoSmithKline, Tao Li, was also charged as part of the five. She has a change of plea hearing scheduled before the court in a few weeks, but it was unclear if she would be pleading to the same charge as Xue.

Slomsky set a sentencing hearing for December 18, but agreed to hold an evidentiary hearing prior to that date that will largely focus on the difference between prosecutors’ and defense attorneys’ arguments about how serious the crime was and how much potential financial damage was caused.

“There are vast differences between the parties as to the value and importance of the information stolen,” Assistant US Attorney Robert Livermore said.

Federal prosecutors have had to drop charges or withdraw cases in several other high-profile trade secret cases in recent years, including that of Temple University professor Xiaoxing Xi, who was accused of stealing sensitive technology involving superconductivity in 2015.

Charges were dropped when investigators realized the information shared did not amount to trade secrets.